Water-in-fuel can cause corrosion and other damage to engine components such as fuel injection systems. As such, diesel engines typically employ a fuel/water separator to remove water from the fuel prior to fuel injection into the engine system. A water reservoir serves to collect the separated water from the fuel/water separator so that it can be manually drained at a suitable time such as when the engine is off, or automatically drained to the exhaust system under suitable conditions. Water reservoir sensors are used to determine when the reservoir levels are high and to trigger warning indicators to the vehicle operator signaling when reservoir draining is due.
Fisher et. al. (US 20110259088) describes a high water content fuel detection system where sensors determine a rate of accumulation of water in a water filter sump, which is monitored as an indication of the fuel quality. Depending on the sensor output, the system may request draining of the fuel filtration or fuel tank sump, and alert the operator of high water content fuel.
The inventors have recognized potential issues with the above system. Namely, conventional warning indicators only alert operators to high water reservoir levels or high water reservoir accumulation rates, and the operator has no way of knowing if the water capacity of the water separator reservoir has been exceeded. In particular, if a vehicle is refueled with high water content fuel, the risk of passing water to the fuel injection system is increased because water will immediately and steadily accumulate in the reservoir as fuel is consumed during vehicle operation. Accordingly, water can potentially be passed to the fuel injection system, resulting in degradation.
One approach which at least partially addresses the above issues is a method, comprising generating a water-in-fuel indication responsive to a water-in-fuel content increasing more than a threshold amount within a threshold time of a refueling event. In another embodiment, a method may comprise, responsive to a refueling condition and following completion of refueling, measuring a change in a water-in-fuel content, and generating a water-in-fuel operator indication if the change in the water-in-fuel content is greater than a non-zero threshold amount. In this manner, it may be possible to achieve the technical result of identifying a large increase in water volume in a short time interval following a refueling event and generate an operator warning to reduce degradation to the engine system.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.